Medovir (Aciclovir)

• Aciclovir is an antiviral agent used to treat infections caused by herpesviruses.
• Herpes simplex virus infection: Reduces lesion duration, limits viral shedding, and speeds recovery of mucocutaneous lesions in immunocompetent and immunocompromised patients.
• Varicella‑zoster virus infection (shingles): Alleviates acute neuropathic pain, accelerates crust formation, and shortens overall disease course in adults.
• Herpes encephalitis: Provides antiviral therapy that limits viral replication in the central nervous system, improving survival and neurological outcomes when started early.
• Severe HSV or VZV infection in immunocompromised patients: Enables systemic control of disseminated disease, reducing organ involvement and mortality risk.

• Aciclovir is a nucleoside analogue that, after intracellular phosphorylation by viral thymidine kinase, is converted to aciclovir triphosphate. The triphosphate competitively inhibits viral DNA polymerase, causing premature chain termination during viral DNA synthesis, thereby preventing replication of herpes simplex and varicella‑zoster viruses. The drug exhibits low affinity for host DNA polymerases, resulting in selective antiviral activity with minimal impact on human cellular replication.

Aciclovir administered intravenously can be associated with a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Fever: Transient elevation of body temperature, usually mild and self‑limiting.
• Headache: Mild to moderate headache occurring during or shortly after infusion.
• Nausea: Gastrointestinal discomfort, nausea or occasional vomiting during treatment.
• Injection site reactions: Redness, pain, swelling or phlebitis at the intravenous site.

Serious or Rare Side Effects

• Nephrotoxicity: Acute kidney injury manifested by rising creatinine, especially with rapid infusion or pre‑existing renal disease.
• Neurotoxicity: Confusion, hallucinations, seizures or tremor in patients with high plasma concentrations.
• Hematologic abnormalities: Thrombocytopenia or leukopenia observed in rare cases.
• Severe hypersensitivity: Anaphylactic reactions, widespread rash or angioedema requiring immediate medical attention.

When using Medovir, clinicians should observe several precautionary measures to minimize risk and ensure optimal therapy.

• Renal function assessment: Evaluate baseline kidney function and adjust dose in patients with impairment.
• Hydration status: Ensure adequate hydration before and during infusion to reduce renal toxicity.
• Infusion rate: Administer intravenously over the recommended period to avoid rapid plasma peaks.
• Concomitant nephrotoxic drugs: Avoid or monitor use of other agents that may impair renal function.
• Pregnancy and lactation: Use only if potential benefit justifies potential risk, as safety data are limited.
• Store at 2-8°C: Keep refrigerated, protect from light, do not freeze or shake.

Aciclovir may interact with other medicines, influencing its efficacy or safety profile.

Major Interactions (Avoid)

• Probenecid: Decreases renal clearance of aciclovir, increasing plasma concentrations and toxicity risk.
• Cimetidine: Reduces renal tubular secretion, potentially raising aciclovir levels.
• Nephrotoxic agents (e.g., aminoglycosides, amphotericin B): Combined use heightens risk of kidney injury.

Moderate Interactions (Monitor Closely)

• NSAIDs: May affect renal function, requiring monitoring of kidney parameters.
• Immunosuppressants (e.g., cyclosporine): May increase risk of neurotoxicity; observe neurological status.
• Other antivirals (e.g., ganciclovir): Potential additive bone marrow suppression; monitor blood counts.